The ubiquitous blue “Like” or “Share” buttons that you see all over the Internet are hiding an ugly secret. Starting this month, Facebook will use them to track your visit to every Web page that displays the buttons–even if you don’t click on anything.

Facebook will use the data it collects to build a dossier of your browsing habits, logging every site you visit, so it can learn those last few details about your life that it doesn’t already know. And there’s nothing you can do about it, short of staying totally logged out of the social media site or tracking down and installing a special browser extension to protect from this kind of sneaky behavior.